Glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) is an enzyme, which catalyzes the release of D-glucose from the non-reducing ends of starch or related oligo- and polysaccharide molecules. Glucoamylases are produced by several filamentous fungi and yeast, with those from Aspergillus being commercially most important.
Commercially, glucoamylases are used to convert starchy material, which is already partially hydrolyzed by an alpha-amylase, to glucose. The glucose may then be converted directly or indirectly into a fermentation product using a fermenting organism. Examples of commercial fermentation products include alcohols (e.g., ethanol, methanol, butanol, 1,3-propanediol); organic acids (e.g., citric acid, acetic acid, itaconic acid, lactic acid, gluconic add, gluconate, lactic add, succinic acid, 2,5-diketo-D-gluconic acid); ketones (e.g., acetone); amino acids (e.g., glutamic acid), gases (e.g., H2 and CO2), and more complex compounds, including, for example, antibiotics (e.g., penicillin and tetracycline); enzymes: vitamins (e.g., riboflavin, B12, beta-carotene), hormones, and other compounds which are difficult to produce synthetically. Fermentation processes are also commonly used in the consumable alcohol (e.g., beer and wine), dairy (e.g., in the production of yoghurt and cheese), leather, and tobacco industries.
The end product may also be syrup. For instance, the end product may be glucose, but may also be converted, e.g., by glucose isomerase to fructose or a mixture composed almost equally of glucose and fructose. This mixture, or a mixture further enriched with fructose, is the most commonly used high fructose corn syrup (HFCS) commercialized throughout the world.
Boel et al. (1984), EMBO J. 3 (5), p. 1097-1102 disclose Aspergillus niger G1 or G2 glucoamylase.
U.S. Pat. No. 4,727,046 discloses a glucoamylase derived from Corticium rolfsii which is also referred to as Athelia rolfsii. 
WO 84/02921 discloses a glucoamylase derived from Aspergillus awamori. 
WO 99/28248 discloses a glucoamylase derived from Talaromyces emersonii. 
WO 00/75296 discloses a glucoamylase derived from Thermoascus crustaceus. 
WO 2006/069289 discloses glucoamylases derived from Trametes cingulate, Pachykytospora papyracea, and Leucopaxillus giganteus. 
It is an object of the present invention to provide polypeptides having glucoamylase activity and polynucleotides encoding the polypeptides and which provide a high yield in fermentation product production processes, such as ethanol production processes, including one-step ethanol fermentation processes from un-gelatinized raw (or uncooked) starch.